In recent years a major shift toward mobile computing has taken place due to the abundant availability of various mobile devices. Examples are palmtops, MDA's (Mobile Digital Assistant), PDA's (Personal digital assistants), DAP's (digital audio players), PMP's (Portable media players), digital cameras, cell phones, Pocket PC's and GPS devices (Global Positioning System). These mobile devices may be hand-held or be integrated in a car or other vehicle.
Several factors influenced this dramatic change, but the most relevant has been a combination of multi-touch interface with a range of operating systems allowing for a user interaction experience optimized for touch interface. At the same time, users have started to adopt mobile devices in more and more active contexts: on the train, car, boat, flight, and even bikes. It is a problem that controlling a touch based device while moving (or being part of a moving vehicle) often has the effect that a user inadvertently activates the mobile device or activates the device in a way not intended.